The Patent Literature 1 discloses a terminal, which is arranged to extend from an inside to an outside of a housing made of a resin material in a liquid level sensing apparatus placed in a fuel tank. A seal film is formed in a portion of the terminal, which contacts the housing, to limit intrusion of the fuel into the inside of the housing through a gap between the terminal and the housing. Specifically, a liquid seal agent is coated on a surface of the terminal, and this coated liquid seal agent is solidified to form the seal film.
As shown in FIG. 17, the cross section of this type of terminal 91 is often configured into a rectangular form. One reason for this configuration is that an electrical connection of an external terminal or lead wire (external electrical conductor) to an end portion of the terminal 91 can be easily made. Specifically, when the end portion is configured into a planar plate form, the end portion can be easily, plastically deformed to crimp the lead wire onto the end portion. Alternately, the end portion can be easily electrically connected to the external terminal by welding or soldering. Also, it is easy to implement a structure for electrically connecting the end portion to the external terminal by forming the end portion as a male contact and the external terminal as a female contact.
However, it is found that when a seal film 92 is formed on the terminal 91, which has the rectangular cross section, the following disadvantage may occur. Specifically, in a surface of the terminal 91, at each of four edge lines (edges 91a), which are located at four corners, respectively, of a rectangular cross section of the terminal 91 and extend in a longitudinal direction of the terminal 91 (a direction perpendicular to the plane of FIG. 17), a film thickness of the seal film 92 is thinned due to a surface tension of the liquid seal agent at the time of coating the liquid seal agent on the terminal 91. When the thin portion, which has the thin film thickness, is formed in the seal film 92, a sufficient sealing performance cannot be achieved.
Particularly, a selectable material of the liquid seal agent is limited to, for example, a material that is not deteriorated even upon exposure to the fuel, and thereby a material, which has a large viscosity, cannot be selected as the material of the liquid seal agent. In such a case, the thinning of the film thickness of the seal film 92 on the edge 91a becomes particularly prominent.